Detectives say the woman was attacked by an unknown number of men in an upstairs bedroom at a house on Turner Street, Gorton.

The house party took place on Friday night and continued until well after daylight on Saturday.

Investigators say the victim, aged in her 30s, phoned police after waking in an upstairs bedroom.

A large number of people are believed to have attended the impromptu party over the evening.

Detective Inspector Andy Cunliffe, of GMP's Major Incident Team, urged those at the celebration to phone him.

He said: The victim has been through a shocking ordeal and I am sure the wider community will share our disgust at what's happened.

“The victim is now being supported by specially trained officers and detectives are investigating the rape.

“We believe she was raped by a number of men in an upstairs bedroom while a house party continued downstairs.

“If you went to that party I would urge you to contact the incident room immediately. You may not have been aware of what was going on, but you may have some information that could be vital to the investigation".

Anyone with information is asked to call police on 0161 856 1722 or Crimestoppers on 0888 555 111.